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Hirayama M, Mure LS, Le HD, Panda S. Neuronal reprogramming of mouse and human fibroblasts using transcription factors involved in suprachiasmatic nucleus development. iScience 2024; 27:109051. [PMID: 38384840 PMCID: PMC10879699 DOI: 10.1016/j.isci.2024.109051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/18/2023] [Accepted: 01/23/2024] [Indexed: 02/23/2024] Open
Abstract
The hypothalamic suprachiasmatic nucleus (SCN) is composed of heterogenous populations of neurons that express signaling peptides such as vasoactive intestinal polypeptide (VIP) and arginine vasopressin (AVP) and regulate circadian rhythms in behavior and physiology. SCN neurons acquire functional and morphological specializations from waves of transcription factors (TFs) that are expressed during neurogenesis. However, the in vitro generation of SCN neurons has never been achieved. Here we supplemented a highly efficient neuronal conversion protocol with TFs that are expressed during SCN neurogenesis, namely Six3, Six6, Dlx2, and Lhx1. Neurons induced from mouse and human fibroblasts predominantly exhibited neuronal properties such as bipolar or multipolar morphologies, GABAergic neurons with expression of VIP. Our study reveals a critical contribution of these TFs to the development of vasoactive intestinal peptide (Vip) expressing neurons in the SCN, suggesting the regenerative potential of neuronal subtypes contained in the SCN for future SCN regeneration and in vitro disease remodeling.
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Affiliation(s)
- Masatoshi Hirayama
- Regulatory Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
- Department of Ophthalmology, School of Medicine, Keio University, Tokyo, Japan
| | - Ludovic S. Mure
- Regulatory Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Department of BioMedical Research, University of Bern, Bern, Switzerland
| | - Hiep D. Le
- Regulatory Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Satchidananda Panda
- Regulatory Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
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Myung J, Hong S, Schmal C, Vitet H, Wu MY. Weak synchronization can alter circadian period length: implications for aging and disease conditions. Front Neurosci 2023; 17:1242800. [PMID: 37829718 PMCID: PMC10564985 DOI: 10.3389/fnins.2023.1242800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 08/29/2023] [Indexed: 10/14/2023] Open
Abstract
The synchronization of multiple oscillators serves as the central mechanism for maintaining stable circadian rhythms in physiology and behavior. Aging and disease can disrupt synchronization, leading to changes in the periodicity of circadian activities. While our understanding of the circadian clock under synchronization has advanced significantly, less is known about its behavior outside synchronization, which can also fall within a predictable domain. These states not only impact the stability of the rhythms but also modulate the period length. In C57BL/6 mice, aging, diseases, and removal of peripheral circadian oscillators often result in lengthened behavioral circadian periods. Here, we show that these changes can be explained by a surprisingly simple mathematical relationship: the frequency is the reciprocal of the period, and its distribution becomes skewed when the period distribution is symmetric. The synchronized frequency of a population in the skewed distribution and the macroscopic frequency of combined oscillators differ, accounting for some of the atypical circadian period outputs observed in networks without synchronization. Building on this finding, we investigate the dynamics of circadian outputs in the context of aging and disease, where synchronization is weakened.
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Affiliation(s)
- Jihwan Myung
- Graduate Institute of Mind, Brain and Consciousness (GIMBC), Taipei Medical University, Taipei City, Taiwan
- Brain and Consciousness Research Centre (BCRC), TMU-Shuang Ho Hospital, New Taipei City, Taiwan
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology, Okinawa, Japan
| | - Sungho Hong
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology, Okinawa, Japan
| | - Christoph Schmal
- Institute for Theoretical Biology, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Hélène Vitet
- Graduate Institute of Mind, Brain and Consciousness (GIMBC), Taipei Medical University, Taipei City, Taiwan
- Brain and Consciousness Research Centre (BCRC), TMU-Shuang Ho Hospital, New Taipei City, Taiwan
- Department of Pediatrics, College of Medicine, National Cheng Kung University, Tainan City, Taiwan
| | - Mei-Yi Wu
- Division of Nephrology, Department of Internal Medicine, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan
- Division of Nephrology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
- TMU Research Center of Urology and Kidney, Taipei Medical University, Taipei, Taiwan
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3
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Waddell H, Stevenson TJ, Mole DJ. The role of the circadian rhythms in critical illness with a focus on acute pancreatitis. Heliyon 2023; 9:e15335. [PMID: 37089281 PMCID: PMC10119767 DOI: 10.1016/j.heliyon.2023.e15335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 01/20/2023] [Accepted: 04/03/2023] [Indexed: 04/25/2023] Open
Abstract
Circadian rhythms are responsible for governing various physiological processes, including hormone secretion, immune responses, metabolism, and the sleep/wake cycle. In critical illnesses such as acute pancreatitis (AP), circadian rhythms can become dysregulated due to disease. Evidence suggests that time of onset of disease, coupled with peripheral inflammation brought about by AP will impact on the circadian rhythms generated in the central pacemaker and peripheral tissues. Cells of the innate and adaptive immune system are governed by circadian rhythms and the diurnal pattern of expression can be disrupted during disease. Peak circadian immune cell release and gene expression can coincide with AP onset, that may increase pancreatic injury, tissue damage and the potential for systemic inflammation and multiple organ failure to develop. Here, we provide an overview of the role of circadian rhythms in AP and the underpinning inflammatory mechanisms to contextualise ongoing research into the chronobiology and chronotherapeutics of AP.
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Affiliation(s)
- Heather Waddell
- Medical Research Council Centre for Inflammation Research, Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, EH16 4TJ, UK
| | - Tyler J. Stevenson
- Institute of Biodiversity and Animal Health and Comparative Medicine, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G61 1QH, UK
| | - Damian J. Mole
- Medical Research Council Centre for Inflammation Research, Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, EH16 4TJ, UK
- Clinical Surgery, School of Clinical Sciences and Community Health, The University of Edinburgh, Edinburgh, EH16 4SB, UK
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Li Z, Li Y, Xu X, Gu J, Chen H, Gui Y. Exosomes rich in Wnt5 improved circadian rhythm dysfunction via enhanced PPARγ activity in the 6-hydroxydopamine model of Parkinson's disease. Neurosci Lett 2023; 802:137139. [PMID: 36813077 DOI: 10.1016/j.neulet.2023.137139] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/11/2023] [Accepted: 02/17/2023] [Indexed: 02/22/2023]
Abstract
Sleep disorder is one of the most common non-motor symptoms in Parkinson's disease (PD) and even appear as early symptoms. Here we investigated the therapeutic potential of mesenchymal stem cell-derived exosomes (MSC-EXOs) on sleep disorder in PD rats. 6-hydroxydopa (6-OHDA) was used to establish the PD rat model. BMSCquiescent-EXO and BMSCinduced-EXO groups were given intravenous injection 100 µg/g per day for 4 weeks, while control groups were given intravenous injection of the same volume of normal saline. The total sleep time, slow-wave sleep time and fast-wave sleep time in the BMSCquiescent-EXO and BMSCinduced-EXO groups were significantly prolonged (P < 0.05) compared with PD group, while the awakening time was significantly shortened (P < 0.05). In addition, increased levels of dopamine (P < 0.05) and 5-hydroxytryptamine (P < 0.05) levels were observed in the striatum of BMSCquiescent-EXO and BMSCinduced-EXO groups. Further, qPCR and western blot revealed that the mRNA levels of CLOCK, BMAL1 and PER2 in suprachiasmatic nucleus (SCN) were notably increased in BMSCquiescent-EXO and BMSCinduced-EXO groups compared to those from PD rats. More importantly, peroxisome proliferation-activated receptor γ (PPARγ) activities were significantly enhanced after treatment with BMSCquiescent-EXO and BMSCinduced-EXO. JC-1 fluorescence staining showed that mitochondrial membrane potential imbalance was repaired after inoculation of BMSCinduced-EXO. In summary, MSC-EXOs showed the improvement of sleep disorder in PD rats through recovering circadian rhythm associated gene expression. The potential mechanisms may be related with increased PPARγ activities and rescued mitochondrial membrane potential imbalance in Parkinson striatum.
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Affiliation(s)
- Zongshan Li
- Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Yongang Li
- Department of Neurology, First People' Hospital of Wenling, Wenling, Zhejiang 317599, China
| | - Xiaomin Xu
- Department of Neurology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, China
| | - Jiachen Gu
- Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Huimin Chen
- Department of Neurology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, China
| | - Yaxing Gui
- Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China.
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Abstract
INTRODUCTION The etiology of transient global amnesia (TGA) is still a matter of debate. Based, among others, on the observation of a close temporal relation between certain events and subsequent TGA episodes, recent proposals discuss the relevance of stress-associated processes impacting on hippocampal functioning. Circadian, infra- and ultradian rhythmicity has been found to play a relevant role in the multifactorial pathomechanisms of various disorders but has not been thoroughly studied in TGA. METHODS Data of patients with a final diagnosis of TGA were collected in Mannheim, Germany (06/1999-01/2018, n = 404), and in the Kansai district, Japan (04/2006-03/2018, n = 261). Chronological patterns of TGA occurrence were determined. RESULTS Significant circadian rhythmicity of TGA occurrence with bimodal peaks (mid-morning, late afternoon) was found for the entire population (p = 0.002) and for either sub-cohort (Mannheim: p = 0.003, Kansai: p = 0.007). This finding was confirmed for either sex (women: p = 0.004, men: p = 0.004) and different age groups (< 65 years: p = 0.0009, ≥ 65 years: p = 0.003). There was no variation according to day of the week, month or season, but the proportion of patients with a weekday episode was significantly higher in the Mannheim cohort (p = 0.002). DISCUSSION We identified a robust circadian rhythm in TGA occurrence which remarkably applied to either of the two study sites located on different continents and which was independent of sex and age. In light of abundant evidence of circadian rhythmicity of both, components of the human stress response system and memory, chronobiological analyses may provide an opportunity to further uncover the mechanisms underlying TGA.
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Abstract
We investigate oscillations in coupled systems. The methodology is based on the Hopf bifurcation theorem and a condition extended from the Routh–Hurwitz criterion. Such a condition leads to locating the bifurcation values of the parameters. With such an approach, we analyze a single-cell system modeling the minimal genetic negative feedback loop and the coupled-cell system composed by these single-cell systems. We study the oscillatory properties for these systems and compare these properties between the model with Hill-type repression and the one with protein-sequestration-based repression. As the parameters move from the Hopf bifurcation value for single cells to the one for coupled cells, we compute the eigenvalues of the linearized systems to obtain the magnitude of the collective frequency when the periodic solution of the coupled-cell system is generated. Extending from this information on the parameter values, we further compute and compare the collective frequency for the coupled-cell system and the average frequency of the decoupled individual cells. To compare these scenarios with other biological oscillators, we perform parallel analysis and computations on a segmentation clock model.
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Roy K, Maji D, Deb I. Oxygen glucose deprivation impairs circadian clock genes expressions in Neuro 2A neuroblastoma cells unlike C6 glioma. BIOL RHYTHM RES 2021. [DOI: 10.1080/09291016.2021.1911551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Kaninika Roy
- Department of Biochemistry, University of Calcutta, Kolkata, India
| | - Daytee Maji
- Department of Biochemistry, University of Calcutta, Kolkata, India
| | - Ishani Deb
- Department of Biochemistry, University of Calcutta, Kolkata, India
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Belle MDC, Baño-Otalora B, Piggins HD. Perforated Multi-Electrode Array Recording in Hypothalamic Brain Slices. Methods Mol Biol 2021; 2130:263-285. [PMID: 33284451 DOI: 10.1007/978-1-0716-0381-9_20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The ability to record ensemble action potential (AP) discharge frequencies from large populations of neurons over extended periods of time in vitro offers clear advantages in neuroscience and circadian biology research. Here, we provide an overview of a step-by-step method to perform multisite extracellular AP activity recordings in suprachiasmatic and mediobasal hypothalamic nuclei brain slices, using a state-of-the-art perforated multielectrode array system. Further, we describe in detail a setup architecture which systematically delivers stable, high-quality recordings with excellent anatomical accuracy and consistency. We also provide some procedural, technical, and methodological troubleshooting notes and examples of good quality recordings.
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Affiliation(s)
- Mino D C Belle
- Faculty of Biology, Medicine, and Health, AV Hill Building, University of Manchester, Manchester, UK.
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK.
| | - Beatriz Baño-Otalora
- Faculty of Biology, Medicine, and Health, AV Hill Building, University of Manchester, Manchester, UK
| | - Hugh D Piggins
- Faculty of Biology, Medicine, and Health, AV Hill Building, University of Manchester, Manchester, UK
- School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, UK
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Pronina TS, Dil’mukhametova LK, Nikishina YO, Murtazina AR, Ugryumov MV. Synthesis of Dopamine by Non-Dopaminergic Neurons Containing Aromatic Amino Acid Decarboxylase in the Suprachiasmatic Nucleus of Rats in Ontogeny. NEUROCHEM J+ 2020. [DOI: 10.1134/s1819712420020099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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Pronina TS, Kolacheva AA, Dil'muhametova LK, Nikishina YO, Suhinich KK, Ugrumov MV. Characteristic of Dopamine-Producing System and Dopamine Receptors in the Suprachiasmatic Nucleus in Rats in Ontogenesis. DOKL BIOCHEM BIOPHYS 2020; 490:34-37. [PMID: 32342310 DOI: 10.1134/s1607672920010123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 10/30/2019] [Accepted: 10/30/2019] [Indexed: 11/23/2022]
Abstract
One of the features of the developing suprachiasmatic nucleus (SCN), the "biological clock" of the body, is the early expression of dopamine (DA) receptors in the absence of dopaminergic neurons as a source of DA. Only recently we showed that DA in SCN is synthesized together by nerve fibers containing only tyrosine hydroxylase (TH) and neurons containing only aromatic L-amino acid decarboxylase (AADC). This study was aimed to assess specific characteristics of the phenotype of TH-fibers in ontogenesis. For this purpose, PCR and immunohistochemical analysis of the expression of genes and proteins such as TH, AADC, vesicular monoamine transporter (VMAT), and receptors for DA (D1, D2) was performed. We have detected numerous TH-immunoreactive fibers in SCN of young and adult rats. VMAT was observed in some of them, which suggests vesicular storage of L-DOPA. Considering the key role of TH-fibers in cooperative synthesis of DA, we assumed the presence of their dopamine regulation. Using double immunolabeling, we showed that D1 and D2 are present in TH-fibers in adult rats, and only D1 in young rats. According to PCR, D1 and D2 are also expressed in neurons of SCN in adult rats and only D1 in young rats. Thus, it was shown for the first time that VMAT and D1 are coexpressed in TH-fibers synthesizing L-DOPA in SCN in young and adult rats, and also D2 receptors in adult rats, which suggests vesicular storage and dopamine regulation of L-DOPA secretion, respectively.
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Affiliation(s)
- T S Pronina
- Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia.
| | - A A Kolacheva
- Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia
| | - L K Dil'muhametova
- Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia
| | - Yu O Nikishina
- Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia
| | - K K Suhinich
- Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia
| | - M V Ugrumov
- Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia
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Pilorz V, Astiz M, Heinen KO, Rawashdeh O, Oster H. The Concept of Coupling in the Mammalian Circadian Clock Network. J Mol Biol 2020; 432:3618-3638. [PMID: 31926953 DOI: 10.1016/j.jmb.2019.12.037] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 12/22/2019] [Accepted: 12/23/2019] [Indexed: 12/13/2022]
Abstract
The circadian clock network regulates daily rhythms in mammalian physiology and behavior to optimally adapt the organism to the 24-h day/night cycle. A central pacemaker, the hypothalamic suprachiasmatic nucleus (SCN), coordinates subordinate cellular oscillators in the brain, as well as in peripheral organs to align with each other and external time. Stability and coordination of this vast network of cellular oscillators is achieved through different levels of coupling. Although coupling at the molecular level and across the SCN is well established and believed to define its function as pacemaker structure, the notion of coupling in other tissues and across the whole system is less well understood. In this review, we describe the different levels of coupling in the mammalian circadian clock system - from molecules to the whole organism. We highlight recent advances in gaining knowledge of the complex organization and function of circadian network regulation and its significance for the generation of stable but plastic intrinsic 24-h rhythms.
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Affiliation(s)
- Violetta Pilorz
- University of Lübeck, Institute of Neurobiology, Center of Brain, Behavior and Metabolism, Marie-Curie-Strasse, 23562, Luebeck, Germany
| | - Mariana Astiz
- University of Lübeck, Institute of Neurobiology, Center of Brain, Behavior and Metabolism, Marie-Curie-Strasse, 23562, Luebeck, Germany
| | - Keno Ole Heinen
- University of Lübeck, Institute of Neurobiology, Center of Brain, Behavior and Metabolism, Marie-Curie-Strasse, 23562, Luebeck, Germany
| | - Oliver Rawashdeh
- The University of Queensland, School of Biomedical Sciences, Faculty of Medicine, St Lucia Qld, 4071, Australia
| | - Henrik Oster
- University of Lübeck, Institute of Neurobiology, Center of Brain, Behavior and Metabolism, Marie-Curie-Strasse, 23562, Luebeck, Germany.
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Chowdhury D, Wang C, Lu AP, Zhu HL. Understanding Quantitative Circadian Regulations Are Crucial Towards Advancing Chronotherapy. Cells 2019; 8:cells8080883. [PMID: 31412622 PMCID: PMC6721722 DOI: 10.3390/cells8080883] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 08/01/2019] [Accepted: 08/09/2019] [Indexed: 12/19/2022] Open
Abstract
Circadian rhythms have a deep impact on most aspects of physiology. In most organisms, especially mammals, the biological rhythms are maintained by the indigenous circadian clockwork around geophysical time (~24-h). These rhythms originate inside cells. Several core components are interconnected through transcriptional/translational feedback loops to generate molecular oscillations. They are tightly controlled over time. Also, they exert temporal controls over many fundamental physiological activities. This helps in coordinating the body’s internal time with the external environments. The mammalian circadian clockwork is composed of a hierarchy of oscillators, which play roles at molecular, cellular, and higher levels. The master oscillation has been found to be developed at the hypothalamic suprachiasmatic nucleus in the brain. It acts as the core pacemaker and drives the transmission of the oscillation signals. These signals are distributed across different peripheral tissues through humoral and neural connections. The synchronization among the master oscillator and tissue-specific oscillators offer overall temporal stability to mammals. Recent technological advancements help us to study the circadian rhythms at dynamic scale and systems level. Here, we outline the current understanding of circadian clockwork in terms of molecular mechanisms and interdisciplinary concepts. We have also focused on the importance of the integrative approach to decode several crucial intricacies. This review indicates the emergence of such a comprehensive approach. It will essentially accelerate the circadian research with more innovative strategies, such as developing evidence-based chronotherapeutics to restore de-synchronized circadian rhythms.
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Affiliation(s)
- Debajyoti Chowdhury
- HKBU Institute for Research and Continuing Education, Shenzhen 518057, China
- Institute of Integrated Bioinfomedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong 999077, China
| | - Chao Wang
- HKBU Institute for Research and Continuing Education, Shenzhen 518057, China
- Institute of Integrated Bioinfomedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong 999077, China
| | - Ai-Ping Lu
- HKBU Institute for Research and Continuing Education, Shenzhen 518057, China.
- Institute of Integrated Bioinfomedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong 999077, China.
| | - Hai-Long Zhu
- HKBU Institute for Research and Continuing Education, Shenzhen 518057, China.
- Institute of Integrated Bioinfomedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong 999077, China.
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Salaberry NL, Hamm H, Felder-Schmittbuhl MP, Mendoza J. A suprachiasmatic-independent circadian clock(s) in the habenula is affected by Per gene mutations and housing light conditions in mice. Brain Struct Funct 2018; 224:19-31. [PMID: 30242505 DOI: 10.1007/s00429-018-1756-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 09/12/2018] [Indexed: 01/08/2023]
Abstract
For many years, the suprachiasmatic nucleus (SCN) was considered as the unique circadian pacemaker in the mammalian brain. Currently, it is known that other brain areas are able to oscillate in a circadian manner. However, many of them are dependent on, or synchronized by, the SCN. The Habenula (Hb), localized in the epithalamus, is a key nucleus for the regulation of monoamine activity (dopamine, serotonin) and presents circadian features; nonetheless, the clock properties of the Hb are not fully described. Here, we report, first, circadian expression of clock genes in the lateral habenula (LHb) under constant darkness (DD) condition in wild-type mice which is disturbed in double Per1-/--Per2Brdm1 clock-mutant mice. Second, using Per2::luciferase transgenic mice, we observed a self-sustained oscillatory ability (PER2::LUCIFERASE bioluminescence rhythmicity) in the rostral and caudal part of the Hb of arrhythmic SCN-ablated animals. Finally, in Per2::luciferase mice exposed to different lighting conditions (light-dark, constant darkness or constant light), the period or amplitude of PER2 oscillations, in both the rostral and caudal Hb, were similar. However, under DD condition or from SCN-lesioned mice, these two Hb regions were out of phase, suggesting an uncoupling of two putative Hb oscillators. Altogether, these results suggest that an autonomous clock in the rostral and caudal part of the Hb requires integrity of circadian genes to tick, and light information or SCN innervation to keep synchrony. The relevance of the Hb timing might reside in the regulation of circadian functions linked to motivational (reward) and emotional (mood) processes.
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Affiliation(s)
- Nora L Salaberry
- Institute of Cellular and Integrative Neurosciences, CNRS UPR-3212, 5 rue Blaise Pascal, 67000, Strasbourg, France
| | - Hélène Hamm
- Institute of Cellular and Integrative Neurosciences, CNRS UPR-3212, 5 rue Blaise Pascal, 67000, Strasbourg, France
| | | | - Jorge Mendoza
- Institute of Cellular and Integrative Neurosciences, CNRS UPR-3212, 5 rue Blaise Pascal, 67000, Strasbourg, France.
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Li C, Balazsi G. A landscape view on the interplay between EMT and cancer metastasis. NPJ Syst Biol Appl 2018; 4:34. [PMID: 30155271 PMCID: PMC6107626 DOI: 10.1038/s41540-018-0068-x] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 07/02/2018] [Accepted: 07/04/2018] [Indexed: 12/13/2022] Open
Abstract
The epithelial-mesenchymal transition (EMT) is a basic developmental process that converts epithelial cells to mesenchymal cells. Although EMT might promote cancer metastasis, the molecular mechanisms for it remain to be fully clarified. To address this issue, we constructed an EMT-metastasis gene regulatory network model and quantified the potential landscape of cancer metastasis-promoting system computationally. We identified four steady-state attractors on the landscape, which separately characterize anti-metastatic (A), metastatic (M), and two other intermediate (I1 and I2) cell states. The tetrastable landscape and the existence of intermediate states are consistent with recent single-cell measurements. We identified one of the two intermediate states I1 as the EMT state. From a MAP approach, we found that for metastatic progression cells need to first undergo EMT (enter the I1 state), and then become metastatic (switch from the I1 state to the M state). Specifically, for metastatic progression, EMT genes (such as ZEB) should be activated before metastasis genes (such as BACH1). This suggests that temporal order is important for the activation of cellular programs in biological systems, and provides a possible mechanism of EMT-promoting cancer metastasis. To identify possible therapeutic targets from this landscape view, we performed sensitivity analysis for individual molecular factors, and identified optimal interventions for landscape control. We found that minimizing transition actions more effectively identifies optimal combinations of targets that induce transitions between attractors than single-factor sensitivity analysis. Overall, the landscape view not only suggests that intermediate states increase plasticity during cell fate decisions, providing a possible source for tumor heterogeneity that is critically important in metastatic progress, but also provides a way to identify therapeutic targets for preventing cancer progression.
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Affiliation(s)
- Chunhe Li
- Shanghai Center for Mathematical Sciences, Fudan University, Shanghai, China
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
| | - Gabor Balazsi
- The Louis and Beatrice Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, New York, USA
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, USA
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15
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Honma S. The mammalian circadian system: a hierarchical multi-oscillator structure for generating circadian rhythm. J Physiol Sci 2018; 68:207-219. [PMID: 29460036 PMCID: PMC10717972 DOI: 10.1007/s12576-018-0597-5] [Citation(s) in RCA: 119] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 01/25/2018] [Indexed: 10/18/2022]
Abstract
The circadian nature of physiology and behavior is regulated by a circadian clock that generates intrinsic rhythms with a periodicity of approximately 24 h. The mammalian circadian system is composed of a hierarchical multi-oscillator structure, with the central clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus regulating the peripheral clocks found throughout the body. In the past two decades, key clock genes have been discovered in mammals and shown to be interlocked in transcriptional and translational feedback loops. At the cellular level, each cell is governed by its own independent clock; and yet, these cellular circadian clocks in the SCN form regional oscillators that are further coupled to one another to generate a single rhythm for the tissue. The oscillatory coupling within and between the regional oscillators appears to be critical for the extraordinary stability and the wide range of adaptability of the circadian clock, the mechanism of which is now being elucidated with newly advanced molecular tools.
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Affiliation(s)
- Sato Honma
- Research and Education Center for Brain Science, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, 060-8638, Japan.
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16
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Szedlak A, Sims S, Smith N, Paternostro G, Piermarocchi C. Cell cycle time series gene expression data encoded as cyclic attractors in Hopfield systems. PLoS Comput Biol 2017; 13:e1005849. [PMID: 29149186 PMCID: PMC5711035 DOI: 10.1371/journal.pcbi.1005849] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 12/01/2017] [Accepted: 10/25/2017] [Indexed: 12/18/2022] Open
Abstract
Modern time series gene expression and other omics data sets have enabled unprecedented resolution of the dynamics of cellular processes such as cell cycle and response to pharmaceutical compounds. In anticipation of the proliferation of time series data sets in the near future, we use the Hopfield model, a recurrent neural network based on spin glasses, to model the dynamics of cell cycle in HeLa (human cervical cancer) and S. cerevisiae cells. We study some of the rich dynamical properties of these cyclic Hopfield systems, including the ability of populations of simulated cells to recreate experimental expression data and the effects of noise on the dynamics. Next, we use a genetic algorithm to identify sets of genes which, when selectively inhibited by local external fields representing gene silencing compounds such as kinase inhibitors, disrupt the encoded cell cycle. We find, for example, that inhibiting the set of four kinases AURKB, NEK1, TTK, and WEE1 causes simulated HeLa cells to accumulate in the M phase. Finally, we suggest possible improvements and extensions to our model. Cell cycle—the process in which a parent cell replicates its DNA and divides into two daughter cells—is an upregulated process in many forms of cancer. Identifying gene inhibition targets to regulate cell cycle is important to the development of effective therapies. Although modern high throughput techniques offer unprecedented resolution of the molecular details of biological processes like cell cycle, analyzing the vast quantities of the resulting experimental data and extracting actionable information remains a formidable task. Here, we create a dynamical model of the process of cell cycle using the Hopfield model (a type of recurrent neural network) and gene expression data from human cervical cancer cells and yeast cells. We find that the model recreates the oscillations observed in experimental data. Tuning the level of noise (representing the inherent randomness in gene expression and regulation) to the “edge of chaos” is crucial for the proper behavior of the system. We then use this model to identify potential gene targets for disrupting the process of cell cycle. This method could be applied to other time series data sets and used to predict the effects of untested targeted perturbations.
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Affiliation(s)
- Anthony Szedlak
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan, United States of America
| | - Spencer Sims
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan, United States of America
| | - Nicholas Smith
- Salgomed Inc., Del Mar, California, United States of America
| | - Giovanni Paternostro
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, United States of America
| | - Carlo Piermarocchi
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan, United States of America
- * E-mail:
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17
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Fernández-Niño M, Giraldo D, Gomez-Porras JL, Dreyer I, González Barrios AF, Arevalo-Ferro C. A synthetic multi-cellular network of coupled self-sustained oscillators. PLoS One 2017; 12:e0180155. [PMID: 28662174 PMCID: PMC5491139 DOI: 10.1371/journal.pone.0180155] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 06/09/2017] [Indexed: 12/21/2022] Open
Abstract
Engineering artificial networks from modular components is a major challenge in synthetic biology. In the past years, single units, such as switches and oscillators, were successfully constructed and implemented. The effective integration of these parts into functional artificial self-regulated networks is currently on the verge of breakthrough. Here, we describe the design of a modular higher-order synthetic genetic network assembled from two independent self-sustained synthetic units: repressilators coupled via a modified quorum-sensing circuit. The isolated communication circuit and the network of coupled oscillators were analysed in mathematical modelling and experimental approaches. We monitored clustering of cells in groups of various sizes. Within each cluster of cells, cells oscillate synchronously, whereas the theoretical modelling predicts complete synchronization of the whole cellular population to be obtained approximately after 30 days. Our data suggest that self-regulated synchronization in biological systems can occur through an intermediate, long term clustering phase. The proposed artificial multicellular network provides a system framework for exploring how a given network generates a specific behaviour.
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Affiliation(s)
| | - Daniel Giraldo
- Grupo de Diseño de Productos y Procesos (GDPP), Departamento de Ingeniería Química, Universidad de los Andes, Bogotá DC, Colombia
| | | | - Ingo Dreyer
- Centro de Bioinformática y Simulación Molecular (CBSM), Universidad de Talca, Talca, Chile
- Heisenberg-Gruppe BPMPB, Universität Potsdam, Potsdam, Germany
| | - Andrés Fernando González Barrios
- Grupo de Diseño de Productos y Procesos (GDPP), Departamento de Ingeniería Química, Universidad de los Andes, Bogotá DC, Colombia
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18
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Monje FJ, Cicvaric A, Acevedo Aguilar JP, Elbau I, Horvath O, Diao W, Glat M, Pollak DD. Disrupted Ultradian Activity Rhythms and Differential Expression of Several Clock Genes in Interleukin-6-Deficient Mice. Front Neurol 2017; 8:99. [PMID: 28382017 PMCID: PMC5360714 DOI: 10.3389/fneur.2017.00099] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 02/28/2017] [Indexed: 12/14/2022] Open
Abstract
The characteristics of the cycles of activity and rest stand out among the most intensively investigated aspects of circadian rhythmicity in humans and experimental animals. Alterations in the circadian patterns of activity and rest are strongly linked to cognitive and emotional dysfunctions in severe mental illnesses such as Alzheimer’s disease (AD) and major depression (MDD). The proinflammatory cytokine interleukin 6 (IL-6) has been prominently associated with the pathogenesis of AD and MDD. However, the potential involvement of IL-6 in the modulation of the diurnal rhythms of activity and rest has not been investigated. Here, we set out to study the role of IL-6 in circadian rhythmicity through the characterization of patterns of behavioral locomotor activity in IL-6 knockout (IL-6 KO) mice and wild-type littermate controls. Deletion of IL-6 did not alter the length of the circadian period or the amount of locomotor activity under either light-entrained or free-running conditions. IL-6 KO mice also presented a normal phase shift in response to light exposure at night. However, the temporal architecture of the behavioral rhythmicity throughout the day, as characterized by the quantity of ultradian activity bouts, was significantly impaired under light-entrained and free-running conditions in IL-6 KO. Moreover, the assessment of clock gene expression in the hippocampus, a brain region involved in AD and depression, revealed altered levels of cry1, dec2, and rev-erb-beta in IL-6 KO mice. These data propose that IL-6 participates in the regulation of ultradian activity/rest rhythmicity and clock gene expression in the mammalian brain. Furthermore, we propose IL-6-dependent circadian misalignment as a common pathogenetic principle in some neurodegenerative and neuropsychiatric disorders.
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Affiliation(s)
- Francisco J Monje
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna , Vienna , Austria
| | - Ana Cicvaric
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna , Vienna , Austria
| | - Juan Pablo Acevedo Aguilar
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna , Vienna , Austria
| | - Immanuel Elbau
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria; Max Planck Institute of Psychiatry, Munich, Germany
| | - Orsolya Horvath
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna , Vienna , Austria
| | - Weifei Diao
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna , Vienna , Austria
| | - Micaela Glat
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna , Vienna , Austria
| | - Daniela D Pollak
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna , Vienna , Austria
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19
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Unique food-entrained circadian rhythm in cysteine414-alanine mutant mCRY1 transgenic mice. Sleep Biol Rhythms 2016; 14:261-269. [PMID: 27441028 PMCID: PMC4932127 DOI: 10.1007/s41105-016-0050-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 01/07/2016] [Indexed: 11/05/2022]
Abstract
Food availability is a potent environmental cue that directs circadian locomotor activity in rodents. Daily scheduled restricted feeding (RF), in which the food available time is restricted for several hours each day, elicits anticipatory activity. This food-anticipatory activity (FAA) is controlled by a food-entrainable oscillator (FEO) that is distinct from the suprachiasmatic nucleus (SCN), the master pacemaker in mammals. In an earlier report, we described generation of transgenic (Tg) mice ubiquitously overexpressing cysteine414-alanine mutant mCRY1. The Tg mice displayed long locomotor free-running periods (approximately 28 h) with rhythm splitting. Furthermore, their locomotor activity immediately re-adjusted to the advance of light–dark cycles (LD), suggesting some disorder in the coupling of SCN neurons. The present study examined the restricted feeding cycle (RF)-induced entrainment of locomotor activity in Tg mice in various light conditions. In LD, wild-type controls showed both FAA and LD-entrained activities. In Tg mice, almost all activity was eventually consolidated to a single bout before the feeding time. The result suggests a possibility that in Tg mice the feeding cycle dominates the LD cycle as an entrainment agent. In constant darkness (DD), wild-type mice exhibited robust free-run activity and FAA during RF. For Tg mice, only the rhythm entrained to RF was observed in DD. Furthermore, after returning to free feeding, the free-run started from the RF-entrained phase. These results suggest that the SCN of Tg mice is entrainable to RF and that the mCRY1 mutation alters the sensitivity of SCN to the cycle of nonphotic zeitgebers.
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20
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Mattis J, Sehgal A. Circadian Rhythms, Sleep, and Disorders of Aging. Trends Endocrinol Metab 2016; 27:192-203. [PMID: 26947521 PMCID: PMC4808513 DOI: 10.1016/j.tem.2016.02.003] [Citation(s) in RCA: 194] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 02/05/2016] [Accepted: 02/08/2016] [Indexed: 10/22/2022]
Abstract
Sleep-wake cycles are known to be disrupted in people with neurodegenerative disorders. These findings are now supported by data from animal models for some of these disorders, raising the question of whether the disrupted sleep/circadian regulation contributes to the loss of neural function. As circadian rhythms and sleep consolidation also break down with normal aging, changes in these may be part of what makes aging a risk factor for disorders like Alzheimer's disease (AD). Mechanisms underlying the connection between circadian/sleep dysregulation and neurodegeneration remain unclear, but several recent studies provide interesting possibilities. While mechanistic analysis is under way, it is worth considering treatment of circadian/sleep disruption as a means to alleviate symptoms of neurodegenerative disorders.
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Affiliation(s)
- Joanna Mattis
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Amita Sehgal
- HHMI, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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21
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Tamaru T, Hattori M, Honda K, Nakahata Y, Sassone-Corsi P, van der Horst GTJ, Ozawa T, Takamatsu K. CRY Drives Cyclic CK2-Mediated BMAL1 Phosphorylation to Control the Mammalian Circadian Clock. PLoS Biol 2015; 13:e1002293. [PMID: 26562092 PMCID: PMC4642984 DOI: 10.1371/journal.pbio.1002293] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 10/06/2015] [Indexed: 12/20/2022] Open
Abstract
Intracellular circadian clocks, composed of clock genes that act in transcription-translation feedback loops, drive global rhythmic expression of the mammalian transcriptome and allow an organism to anticipate to the momentum of the day. Using a novel clock-perturbing peptide, we established a pivotal role for casein kinase (CK)-2-mediated circadian BMAL1-Ser90 phosphorylation (BMAL1-P) in regulating central and peripheral core clocks. Subsequent analysis of the underlying mechanism showed a novel role of CRY as a repressor for protein kinase. Co-immunoprecipitation experiments and real-time monitoring of protein-protein interactions revealed that CRY-mediated periodic binding of CK2β to BMAL1 inhibits BMAL1-Ser90 phosphorylation by CK2α. The FAD binding domain of CRY1, two C-terminal BMAL1 domains, and particularly BMAL1-Lys537 acetylation/deacetylation by CLOCK/SIRT1, were shown to be critical for CRY-mediated BMAL1-CK2β binding. Reciprocally, BMAL1-Ser90 phosphorylation is prerequisite for BMAL1-Lys537 acetylation. We propose a dual negative-feedback model in which a CRY-dependent CK2-driven posttranslational BMAL1-P-BMAL1 loop is an integral part of the core clock oscillator.
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Affiliation(s)
- Teruya Tamaru
- Department of Physiology and Advanced Research Center for Medical Science, Toho University School of Medicine, Tokyo, Japan
| | - Mitsuru Hattori
- Department of Chemistry, The University of Tokyo, Tokyo, Japan
| | - Kousuke Honda
- Department of Chemistry, The University of Tokyo, Tokyo, Japan
| | - Yasukazu Nakahata
- Laboratory of Gene Regulation Research, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Japan
| | - Paolo Sassone-Corsi
- Department of Biological Chemistry, University of California, Irvine, Irvine, California, United States of America
| | | | - Takeaki Ozawa
- Department of Chemistry, The University of Tokyo, Tokyo, Japan
| | - Ken Takamatsu
- Department of Physiology and Advanced Research Center for Medical Science, Toho University School of Medicine, Tokyo, Japan
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22
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Alamilla J, Granados-Fuentes D, Aguilar-Roblero R. The anterior paraventricular thalamus modulates neuronal excitability in the suprachiasmatic nuclei of the rat. Eur J Neurosci 2015; 42:2833-42. [PMID: 26417679 PMCID: PMC4737286 DOI: 10.1111/ejn.13088] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 09/18/2015] [Accepted: 09/24/2015] [Indexed: 11/28/2022]
Abstract
The suprachiasmatic nucleus (SCN) in mammals is the master clock which regulates circadian rhythms. Neural activity of SCN neurons is synchronized to external light through the retinohypothalamic tract (RHT). The paraventricular thalamic nucleus (PVT) is a neural structure that receives synaptic inputs from, and projects back to, the SCN. Lesioning the anterior PVT (aPVT) modifies the behavioral phase response curve induced by short pulses of bright light. In order to study the influence of the aPVT on SCN neural activity, we addressed whether the stimulation of the aPVT can modulate the electrical response of the SCN to either retinal or RHT stimulation. Using in vitro and in vivo recordings, we found a large population of SCN neurons responsive to the stimulation of either aPVT or RHT pathways. Furthermore, we found that simultaneous stimulation of the aPVT and the RHT increased neuronal responsiveness and spontaneous firing rate (SFR) in neurons with a low basal SFR (which also have more negative membrane potentials), such as quiescent and arrhythmic neurons, but no change was observed in neurons with rhythmic firing patterns and more depolarized membrane potentials. These results suggest that inputs from the aPVT could shift the membrane potential of an SCN neuron to values closer to its firing threshold and thus contribute to integration of the response of the circadian clock to light.
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Affiliation(s)
- Javier Alamilla
- CONACYT Research Fellow - Centro de Investigaciones Biomédicas de la Universidad de Colima, Colima, México
| | | | - Raúl Aguilar-Roblero
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apdo. Postal 70-253, 04510, México, DF, México
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23
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Age-Related Changes in the Circadian System Unmasked by Constant Conditions. eNeuro 2015; 2:eN-NWR-0064-15. [PMID: 26464996 PMCID: PMC4596014 DOI: 10.1523/eneuro.0064-15.2015] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 08/17/2015] [Accepted: 08/22/2015] [Indexed: 12/14/2022] Open
Abstract
Circadian timing systems, like most physiological processes, cannot escape the effects of aging. With age, humans experience decreased duration and quality of sleep. Aged mice exhibit decreased amplitude and increased fragmentation of the activity rhythm, and lengthened circadian free-running period in both light-dark (LD) and constant dark (DD) conditions. Several studies have shown that aging impacts neural activity rhythms in the central circadian clock in the suprachiasmatic nucleus (SCN). However, evidence for age-related disruption of circadian oscillations of clock genes in the SCN has been equivocal. We hypothesized that daily exposure to LD cycles masks the full impact of aging on molecular rhythms in the SCN. We performed ex vivo bioluminescent imaging of cultured SCN slices of young and aged PER2::luciferase knock-in (PER2::LUC) mice housed under LD or prolonged DD conditions. Under LD conditions, the amplitude of PER2::LUC rhythms differed only slightly between SCN explants from young and aged animals; under DD conditions, the PER2::LUC rhythms of aged animals showed markedly lower amplitudes and longer circadian periods than those of young animals. Recordings of PER2::LUC rhythms in individual SCN cells using an electron multiplying charge-coupled device camera revealed that aged SCN cells showed longer circadian periods and that the rhythms of individual cells rapidly became desynchronized. These data suggest that aging degrades the SCN circadian ensemble, but that recurrent LD cycles mask these effects. We propose that these changes reflect a decline in pacemaker robustness that could increase vulnerability to environmental challenges, and partly explain age-related sleep and circadian disturbances.
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24
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Krishnan HC, Lyons LC. Synchrony and desynchrony in circadian clocks: impacts on learning and memory. ACTA ACUST UNITED AC 2015; 22:426-37. [PMID: 26286653 PMCID: PMC4561405 DOI: 10.1101/lm.038877.115] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 06/29/2015] [Indexed: 12/11/2022]
Abstract
Circadian clocks evolved under conditions of environmental variation, primarily alternating light dark cycles, to enable organisms to anticipate daily environmental events and coordinate metabolic, physiological, and behavioral activities. However, modern lifestyle and advances in technology have increased the percentage of individuals working in phases misaligned with natural circadian activity rhythms. Endogenous circadian oscillators modulate alertness, the acquisition of learning, memory formation, and the recall of memory with examples of circadian modulation of memory observed across phyla from invertebrates to humans. Cognitive performance and memory are significantly diminished when occurring out of phase with natural circadian rhythms. Disruptions in circadian regulation can lead to impairment in the formation of memories and manifestation of other cognitive deficits. This review explores the types of interactions through which the circadian clock modulates cognition, highlights recent progress in identifying mechanistic interactions between the circadian system and the processes involved in memory formation, and outlines methods used to remediate circadian perturbations and reinforce circadian adaptation.
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Affiliation(s)
- Harini C Krishnan
- Department of Biological Science, Program in Neuroscience, Florida State University, Tallahassee, Florida 32306, USA
| | - Lisa C Lyons
- Department of Biological Science, Program in Neuroscience, Florida State University, Tallahassee, Florida 32306, USA
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25
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Bedont JL, Blackshaw S. Constructing the suprachiasmatic nucleus: a watchmaker's perspective on the central clockworks. Front Syst Neurosci 2015; 9:74. [PMID: 26005407 PMCID: PMC4424844 DOI: 10.3389/fnsys.2015.00074] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 04/23/2015] [Indexed: 11/13/2022] Open
Abstract
The circadian system constrains an organism's palette of behaviors to portions of the solar day appropriate to its ecological niche. The central light-entrained clock in the suprachiasmatic nucleus (SCN) of the mammalian circadian system has evolved a complex network of interdependent signaling mechanisms linking multiple distinct oscillators to serve this crucial function. However, studies of the mechanisms controlling SCN development have greatly lagged behind our understanding of its physiological functions. We review advances in the understanding of adult SCN function, what has been described about SCN development to date, and the potential of both current and future studies of SCN development to yield important insights into master clock function, dysfunction, and evolution.
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Affiliation(s)
- Joseph L Bedont
- Department of Neuroscience, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Seth Blackshaw
- Department of Neuroscience, Johns Hopkins University School of Medicine Baltimore, MD, USA ; Department of Ophthalmology, Johns Hopkins University School of Medicine Baltimore, MD, USA ; Department of Physiology, Johns Hopkins University School of Medicine Baltimore, MD, USA ; Department of Neurology, Johns Hopkins University School of Medicine Baltimore, MD, USA ; Center for High-Throughput Biology, Johns Hopkins University School of Medicine Baltimore, MD, USA
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26
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Kripke DF, Elliott JA, Welsh DK, Youngstedt SD. Photoperiodic and circadian bifurcation theories of depression and mania. F1000Res 2015; 4:107. [PMID: 26180634 PMCID: PMC4490783 DOI: 10.12688/f1000research.6444.1] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/05/2015] [Indexed: 12/26/2022] Open
Abstract
Seasonal effects on mood have been observed throughout much of human history. Seasonal changes in animals and plants are largely mediated through the changing photoperiod (i.e., the photophase or duration of daylight). We review that in mammals, daylight specifically regulates SCN (suprachiasmatic nucleus) circadian organization and its control of melatonin secretion. The timing of melatonin secretion interacts with gene transcription in the pituitary pars tuberalis to modulate production of TSH (thyrotropin), hypothalamic T3 (triiodothyronine), and tuberalin peptides which modulate pituitary production of regulatory gonadotropins and other hormones. Pituitary hormones largely mediate seasonal physiologic and behavioral variations. As a result of long winter nights or inadequate illumination, we propose that delayed morning offset of nocturnal melatonin secretion, suppressing pars tuberalis function, could be the main cause for winter depression and even cause depressions at other times of year. Irregularities of circadian sleep timing and thyroid homeostasis contribute to depression. Bright light and sleep restriction are antidepressant and conversely, sometimes trigger mania. We propose that internal desynchronization or bifurcation of SCN circadian rhythms may underlie rapid-cycling manic-depressive disorders and perhaps most mania. Much further research will be needed to add substance to these theories.
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Affiliation(s)
- Daniel F Kripke
- Department of Psychiatry and Center for Circadian Biology, University of California, San Diego, CA, 92093-0603, USA
| | - Jeffrey A Elliott
- Department of Psychiatry and Center for Circadian Biology, University of California, San Diego, CA, 92093-0603, USA
| | - David K Welsh
- Department of Psychiatry and Center for Circadian Biology, University of California, San Diego, CA, 92093-0603, USA
| | - Shawn D Youngstedt
- College of Nursing and Health Innovation, Arizona State University, Phoenix, AZ, 85004-4431, USA
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27
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Gu F, Han J, Laden F, Pan A, Caporaso NE, Stampfer MJ, Kawachi I, Rexrode KM, Willett WC, Hankinson SE, Speizer FE, Schernhammer ES. Total and cause-specific mortality of U.S. nurses working rotating night shifts. Am J Prev Med 2015; 48:241-52. [PMID: 25576495 PMCID: PMC4339532 DOI: 10.1016/j.amepre.2014.10.018] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 10/01/2014] [Accepted: 10/24/2014] [Indexed: 01/06/2023]
Abstract
BACKGROUND Rotating night shift work imposes circadian strain and is linked to the risk of several chronic diseases. PURPOSE To examine associations between rotating night shift work and all-cause; cardiovascular disease (CVD); and cancer mortality in a prospective cohort study of 74,862 registered U.S. nurses from the Nurses' Health Study. METHODS Lifetime rotating night shift work (defined as ≥3 nights/month) information was collected in 1988. During 22 years (1988-2010) of follow-up, 14,181 deaths were documented, including 3,062 CVD and 5,413 cancer deaths. Cox proportional hazards models estimated multivariable-adjusted hazard ratios (HRs) and 95% CIs. RESULTS All-cause and CVD mortality were significantly increased among women with ≥5 years of rotating night shift work, compared to women who never worked night shifts. Specifically, for women with 6-14 and ≥15 years of rotating night shift work, the HRs were 1.11 (95% CI=1.06, 1.17) and 1.11 (95% CI=1.05, 1.18) for all-cause mortality and 1.19 (95% CI=1.07, 1.33) and 1.23 (95% CI=1.09, 1.38) for CVD mortality. There was no significant association between rotating night shift work and all-cancer mortality (HR≥15years=1.08, 95% CI=0.98, 1.19) or mortality of any individual cancer, with the exception of lung cancer (HR≥15years=1.25, 95% CI=1.04, 1.51). CONCLUSIONS Women working rotating night shifts for ≥5 years have a modest increase in all-cause and CVD mortality; those working ≥15 years of rotating night shift work have a modest increase in lung cancer mortality. These results add to prior evidence of a potentially detrimental effect of rotating night shift work on health and longevity.
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Affiliation(s)
- Fangyi Gu
- Division of Cancer Epidemiology & Genetics, Genetic Epidemiology Branch, National Cancer Institute, Bethesda, Maryland
| | - Jiali Han
- Channing Division of Network Medicine, Harvard School of Public Health, Boston; Clinical Research Program, Department of Dermatology, Harvard School of Public Health, Boston; Department of Epidemiology, Richard M. Fairbanks School of Public Health, Simon Cancer Center, Indiana University, Indianapolis, Indiana
| | - Francine Laden
- Department of Environmental Health, Harvard School of Public Health, Boston; Department of Epidemiology, Harvard School of Public Health, Boston
| | - An Pan
- Saw Swee Hock School of Public Health and Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore
| | - Neil E Caporaso
- Division of Cancer Epidemiology & Genetics, Genetic Epidemiology Branch, National Cancer Institute, Bethesda, Maryland
| | - Meir J Stampfer
- Channing Division of Network Medicine, Harvard School of Public Health, Boston; Department of Epidemiology, Harvard School of Public Health, Boston
| | - Ichiro Kawachi
- Department of Social and Behavioral Sciences, Harvard School of Public Health, Boston
| | - Kathryn M Rexrode
- Division of Preventive Medicine, Harvard School of Public Health, Boston
| | - Walter C Willett
- Department of Nutrition, Harvard School of Public Health, Boston
| | - Susan E Hankinson
- Channing Division of Network Medicine, Harvard School of Public Health, Boston; Division of Biostatistics and Epidemiology, University of Massachusetts, Amherst, Massachusetts
| | - Frank E Speizer
- Channing Division of Network Medicine, Harvard School of Public Health, Boston
| | - Eva S Schernhammer
- Channing Division of Network Medicine, Harvard School of Public Health, Boston; Division of Sleep Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Harvard School of Public Health, Boston; Applied Cancer Research-Institution for Translational Research Vienna (ACR-ITR VIEnna), Vienna, Austria.
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28
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Wellhauser L, Gojska NM, Belsham DD. Delineating the regulation of energy homeostasis using hypothalamic cell models. Front Neuroendocrinol 2015; 36:130-49. [PMID: 25223866 DOI: 10.1016/j.yfrne.2014.09.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 08/28/2014] [Accepted: 09/02/2014] [Indexed: 12/27/2022]
Abstract
Attesting to its intimate peripheral connections, hypothalamic neurons integrate nutritional and hormonal cues to effectively manage energy homeostasis according to the overall status of the system. Extensive progress in the identification of essential transcriptional and post-translational mechanisms regulating the controlled expression and actions of hypothalamic neuropeptides has been identified through the use of animal and cell models. This review will introduce the basic techniques of hypothalamic investigation both in vivo and in vitro and will briefly highlight the key advantages and challenges of their use. Further emphasis will be place on the use of immortalized models of hypothalamic neurons for in vitro study of feeding regulation, with a particular focus on cell lines proving themselves most fruitful in deciphering fundamental basics of NPY/AgRP, Proglucagon, and POMC neuropeptide function.
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Affiliation(s)
- Leigh Wellhauser
- Department of Physiology, University of Toronto, Toronto, Ontario M5G 1A8, Canada
| | - Nicole M Gojska
- Department of Physiology, University of Toronto, Toronto, Ontario M5G 1A8, Canada
| | - Denise D Belsham
- Departments of Physiology, Medicine and OB/GYN, University of Toronto, Toronto, Ontario M5G 1A8, Canada; Division of Cellular and Molecular Biology, Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario M5S 1A8, Canada.
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Meijer JH, Michel S. Neurophysiological Analysis of the Suprachiasmatic Nucleus. Methods Enzymol 2015; 552:75-102. [DOI: 10.1016/bs.mie.2014.11.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Herzog ED, Kiss IZ, Mazuski C. Measuring synchrony in the mammalian central circadian circuit. Methods Enzymol 2014; 552:3-22. [PMID: 25707270 DOI: 10.1016/bs.mie.2014.10.042] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Circadian clocks control daily rhythms in physiology and behavior across all phyla. These rhythms are intrinsic to individual cells that must synchronize to their environment and to each other to anticipate daily events. Recent advances in recording from large numbers of cells for many circadian cycles have enabled researchers to begin to evaluate the mechanisms and consequences of intercellular circadian synchrony. Consequently, methods have been adapted to estimate the period, phase, and amplitude of individual circadian cells and calculate synchrony between cells. Stable synchronization requires that the cells share a common period. As a result, synchronized cells maintain constant phase relationships to each (e.g., with cell 1 peaking an hour before cell 2 each cycle). This chapter reviews how circadian rhythms are recorded from single mammalian cells and details methods for measuring their period and phase synchrony. These methods have been useful, for example, in showing that specific neuropeptides are essential to maintain synchrony among circadian cells.
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Affiliation(s)
- Erik D Herzog
- Department of Biology, Washington University, St. Louis, Missouri, USA.
| | - István Z Kiss
- Department of Chemistry, Saint Louis University, St. Louis, Missouri, USA
| | - Cristina Mazuski
- Department of Biology, Washington University, St. Louis, Missouri, USA
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Kripke DF, Klimecki WT, Nievergelt CM, Rex KM, Murray SS, Shekhtman T, Tranah GJ, Loving RT, Lee HJ, Rhee MK, Shadan FF, Poceta JS, Jamil SM, Kline LE, Kelsoe JR. Circadian polymorphisms in night owls, in bipolars, and in non-24-hour sleep cycles. Psychiatry Investig 2014; 11:345-62. [PMID: 25395965 PMCID: PMC4225198 DOI: 10.4306/pi.2014.11.4.345] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 04/18/2014] [Accepted: 04/18/2014] [Indexed: 12/13/2022] Open
Abstract
People called night owls habitually have late bedtimes and late times of arising, sometimes suffering a heritable circadian disturbance called delayed sleep phase syndrome (DSPS). Those with DSPS, those with more severe progressively-late non-24-hour sleep-wake cycles, and those with bipolar disorder may share genetic tendencies for slowed or delayed circadian cycles. We searched for polymorphisms associated with DSPS in a case-control study of DSPS research participants and a separate study of Sleep Center patients undergoing polysomnography. In 45 participants, we resequenced portions of 15 circadian genes to identify unknown polymorphisms that might be associated with DSPS, non-24-hour rhythms, or bipolar comorbidities. We then genotyped single nucleotide polymorphisms (SNPs) in both larger samples, using Illumina Golden Gate assays. Associations of SNPs with the DSPS phenotype and with the morningness-eveningness parametric phenotype were computed for both samples, then combined for meta-analyses. Delayed sleep and "eveningness" were inversely associated with loci in circadian genes NFIL3 (rs2482705) and RORC (rs3828057). A group of haplotypes overlapping BHLHE40 was associated with non-24-hour sleep-wake cycles, and less robustly, with delayed sleep and bipolar disorder (e.g., rs34883305, rs34870629, rs74439275, and rs3750275 were associated with n=37, p=4.58E-09, Bonferroni p=2.95E-06). Bright light and melatonin can palliate circadian disorders, and genetics may clarify the underlying circadian photoperiodic mechanisms. After further replication and identification of the causal polymorphisms, these findings may point to future treatments for DSPS, non-24-hour rhythms, and possibly bipolar disorder or depression.
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Affiliation(s)
- Daniel F. Kripke
- Department of Psychiatry, University of California, San Diego, CA, USA
- Viterbi Family Sleep Center, Scripps Clinic, La Jolla, CA, USA
| | - Walter T. Klimecki
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ, USA
| | | | - Katharine M. Rex
- Department of Psychiatry, University of California, San Diego, CA, USA
| | - Sarah S. Murray
- Department of Pathology, Center for Advanced Laboratory Medicine, University of California, San Diego, CA, USA
| | - Tatyana Shekhtman
- Department of Psychiatry, University of California, San Diego, CA, USA
- VA San Diego Healthcare System, San Diego, CA, USA
| | - Gregory J. Tranah
- California Pacific Medical Center Research Institute, San Francisco, CA, USA
| | | | - Heon-Jeong Lee
- Department of Psychiatry, Korea University College of Medicine, Seoul, Republic of Korea
| | - Min Kyu Rhee
- Department of Psychology, Gyeongsang National University, Jinju, Republic of Korea
| | | | | | - Shazia M. Jamil
- Viterbi Family Sleep Center, Scripps Clinic, La Jolla, CA, USA
| | | | - John R. Kelsoe
- Department of Psychiatry, University of California, San Diego, CA, USA
- VA San Diego Healthcare System, San Diego, CA, USA
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Tigges J, Krutmann J, Fritsche E, Haendeler J, Schaal H, Fischer JW, Kalfalah F, Reinke H, Reifenberger G, Stühler K, Ventura N, Gundermann S, Boukamp P, Boege F. The hallmarks of fibroblast ageing. Mech Ageing Dev 2014; 138:26-44. [PMID: 24686308 DOI: 10.1016/j.mad.2014.03.004] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Revised: 03/11/2014] [Accepted: 03/18/2014] [Indexed: 12/26/2022]
Abstract
Ageing is influenced by the intrinsic disposition delineating what is maximally possible and extrinsic factors determining how that frame is individually exploited. Intrinsic and extrinsic ageing processes act on the dermis, a post-mitotic skin compartment mainly consisting of extracellular matrix and fibroblasts. Dermal fibroblasts are long-lived cells constantly undergoing damage accumulation and (mal-)adaptation, thus constituting a powerful indicator system for human ageing. Here, we use the systematic of ubiquitous hallmarks of ageing (Lopez-Otin et al., 2013, Cell 153) to categorise the available knowledge regarding dermal fibroblast ageing. We discriminate processes inducible in culture from phenomena apparent in skin biopsies or primary cells from old donors, coming to the following conclusions: (i) Fibroblasts aged in culture exhibit most of the established, ubiquitous hallmarks of ageing. (ii) Not all of these hallmarks have been detected or investigated in fibroblasts aged in situ (in the skin). (iii) Dermal fibroblasts aged in vitro and in vivo exhibit additional features currently not considered ubiquitous hallmarks of ageing. (iv) The ageing process of dermal fibroblasts in their physiological tissue environment has only been partially elucidated, although these cells have been a preferred model of cell ageing in vitro for decades.
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Affiliation(s)
- Julia Tigges
- Leibniz Research Institute for Environmental Medicine (IUF), Düsseldorf, Germany
| | - Jean Krutmann
- Leibniz Research Institute for Environmental Medicine (IUF), Düsseldorf, Germany
| | - Ellen Fritsche
- Leibniz Research Institute for Environmental Medicine (IUF), Düsseldorf, Germany
| | - Judith Haendeler
- Leibniz Research Institute for Environmental Medicine (IUF), Düsseldorf, Germany; Institute of Clinical Chemistry and Laboratory Diagnostics, Heinrich-Heine-University, Med. Faculty, Düsseldorf, Germany
| | - Heiner Schaal
- Center for Microbiology and Virology, Institute of Virology, Heinrich-Heine-University, Med. Faculty, D-40225 Düsseldorf, Germany
| | - Jens W Fischer
- Institute for Pharmacology and Clinical Pharmacology, Heinrich-Heine-University, Med. Faculty, Düsseldorf, Germany
| | - Faiza Kalfalah
- Institute of Clinical Chemistry and Laboratory Diagnostics, Heinrich-Heine-University, Med. Faculty, Düsseldorf, Germany
| | - Hans Reinke
- Leibniz Research Institute for Environmental Medicine (IUF), Düsseldorf, Germany; Institute of Clinical Chemistry and Laboratory Diagnostics, Heinrich-Heine-University, Med. Faculty, Düsseldorf, Germany
| | - Guido Reifenberger
- Department of Neuropathology, Heinrich-Heine-University, Med. Faculty, Düsseldorf, Germany
| | - Kai Stühler
- Institute for Molecular Medicine, Heinrich-Heine-University, Med. Faculty, Düsseldorf, Germany; Molecular Proteomics Laboratory, Centre for Biological and Medical Research (BMFZ), Heinrich-Heine-University, Düsseldorf, Germany
| | - Natascia Ventura
- Leibniz Research Institute for Environmental Medicine (IUF), Düsseldorf, Germany; Institute of Clinical Chemistry and Laboratory Diagnostics, Heinrich-Heine-University, Med. Faculty, Düsseldorf, Germany
| | | | - Petra Boukamp
- German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Fritz Boege
- Institute of Clinical Chemistry and Laboratory Diagnostics, Heinrich-Heine-University, Med. Faculty, Düsseldorf, Germany.
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Ramsey DJ, Ramsey KM, Vavvas DG. Genetic advances in ophthalmology: the role of melanopsin-expressing, intrinsically photosensitive retinal ganglion cells in the circadian organization of the visual system. Semin Ophthalmol 2013; 28:406-21. [PMID: 24010846 DOI: 10.3109/08820538.2013.825294] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Daily changes in the light-dark cycle are the principal environmental signal that enables organisms to synchronize their internal biology with the 24-hour day-night cycle. In humans, the visual system is integral to photoentrainment and is primarily driven by a specialized class of intrinsically photosensitive retinal ganglion cells (ipRGCs) that express the photopigment melanopsin (OPN4) in the inner retina. These cells project through the retinohypothalamic tract (RHT) to the suprachiasmatic nuclei (SCN) of the hypothalamus, which serves as the body's master biological clock. At the same time, the retina itself possesses intrinsic circadian oscillations, exemplified by diurnal fluctuations in visual sensitivity, neurotransmitter levels, and outer segment turnover rates. Recently, it has been noted that both central and peripheral oscillators share a molecular clock consisting of an endogenous, circadian-driven, transcription-translation feedback loop that cycles with a periodicity of approximately 24 hours. This review will cover the role that melanopsin and ipRGCs play in the circadian organization of the visual system.
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Affiliation(s)
- David J Ramsey
- Retina Service, Harvard Medical School, Massachusetts Eye and Ear Infirmary and Mass General Hospital , Boston, Massachusetts , USA
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Odawara A, Gotoh M, Suzuki I. Control of neural network patterning using collagen gel photothermal etching. LAB ON A CHIP 2013; 13:2040-2046. [PMID: 23615759 DOI: 10.1039/c3lc00036b] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Two-dimensional (2D) micropatterning techniques have been developed to guide dissociated neurons into predefined distributions on solid substrates, such as glass and plastic. Micropatterning methods using three-dimensional (3D) substrates or scaffolds that reproduce aspects of the in vivo microenvironment could facilitate the engineering of functional tissues for transplantation or more robust experimental models. We developed a 3D collagen gel photothermal etching method using an infrared laser that precisely controls the area of cell adhesion and neurite projection by etching a small targeted section of the collage gel. It was then possible to guide neural network formation under microscopic observation. After conventional cell seeding, we succeeded in creating isolated 3D networks, while controlling (1) the number of each neural subtype (neurons, glia, and fluorescently-labeled neurons) and (2) the direction of neurite elongation. Neurons seeded on a 10-μm-thick collagen gel survived longer and projected greater numbers of neurites than neurons growing on 2D culture substrates. Intracellular Ca(2+) imaging revealed both synchronous and discordant oscillations in different neuronal populations that suggested the pattern and strength of synaptic connectivity. This photothermal etching technique allows for the creation of designed 3D neural networks during cultivation for use in studies of synaptic transmission, neuron-glial signaling, pathogenesis, and drug responses.
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Affiliation(s)
- Aoi Odawara
- Graduate School of Bionics, Tokyo University of Technology, 1404-1 katakura, Hachioji, Tokyo 192-0982, Japan
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Ugrumov MV. Brain neurons partly expressing dopaminergic phenotype: location, development, functional significance, and regulation. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2013; 68:37-91. [PMID: 24054140 DOI: 10.1016/b978-0-12-411512-5.00004-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In addition to catecholaminergic neurons possessing all the enzymes of catecholamine synthesis and the specific membrane transporters, neurons partly expressing the catecholaminergic phenotype have been found a quarter of a century ago. Most of them express individual enzymes of dopamine (DA) synthesis, tyrosine hydroxylase (TH), or aromatic l-amino acid decarboxylase (AADC), lacking the DA membrane transporter and the vesicular monoamine transporter, type 2. These so-called monoenzymatic neurons are widely distributed throughout the brain in ontogenesis and adulthood being in some brain regions even more numerous than dopaminergic (DA-ergic) neurons. Individual enzymes of DA synthesis are expressed in these neurons continuously or transiently in norm and pathology. It has been proven that monoenzymatic TH neurons and AADC neurons are capable of producing DA in cooperation. It means that l-3,4-dihydroxyphenylalanine (l-DOPA) synthesized from l-tyrosine in monoenzymatic TH neurons is transported to monoenzymatic AADC neurons for DA synthesis. Such cooperative synthesis of DA is considered as a compensatory reaction under a failure of DA-ergic neurons, for example, in neurodegenerative diseases like hyperprolactinemia and Parkinson's disease. Moreover, l-DOPA, produced in monoenzymatic TH neurons, is assumed to play a role of a neurotransmitter or neuromodulator affecting the target neurons via catecholamine receptors. Thus, numerous widespread neurons expressing individual complementary enzymes of DA synthesis serve to produce DA in cooperation that is a compensatory reaction at failure of DA-ergic neurons.
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Affiliation(s)
- Michael V Ugrumov
- Institute of Developmental Biology and Centre for Brain Research, Russian Academy of Sciences, Moscow, Russia; Institute of Normal Physiology RAMS, Moscow, Russia.
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